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1 | Copyright 1998, O'Reilly & Associates, Inc. |
2 | ||
3 | This package may be copied under the same terms as Perl itself. | |
4 | ||
5 | Disclaimers | |
6 | ----------- | |
7 | This is a work in progress, and relies on bleeding-edge technology | |
8 | from the network. Don't expect not to be surprised occasionally. | |
9 | ||
10 | Requirements | |
11 | ------------ | |
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12 | Under Solaris and GNU/Linux (and other Unix-like systems), Perl 5.005 (or |
13 | later) must be compiled and installed as a shared library (libperl.so). I | |
14 | had to use the system's malloc. JPL was originally built and tested with | |
15 | 5.004_04 and early Java 1.1 development kits. This version has not been | |
16 | well tested under other versions, so you can expect some rough edges. | |
93e0cdbd | 17 | |
35ef589f | 18 | You need JDK 1.1. On Solaris, 1.1.5 has been verified to work. GNU/Linux |
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19 | users can try the latest version (1.1.3 or later) available from (for |
20 | example): | |
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21 | |
22 | ftp://ftp.blackdown.org/pub/Linux/JDK/1.1.3/updates/libjava-1.1.3v2-1.tar.gz | |
23 | ||
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24 | (GNU/Linux users can also try Kaffe (see below).) |
25 | ||
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26 | The get_jdk directory contains a script that will download JDK (but not |
27 | the patch file above) off of the net for you. (This presumes you've | |
28 | already installed the modules mentioned in ../README.) | |
29 | ||
30 | You may need to ensure that all files under the ../jpl directory are writable. | |
31 | install-jpl expects to be run with super-user privileges so that it can | |
32 | put things in the right places. | |
33 | ||
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34 | Microsoft Windows |
35 | ----------------- | |
36 | Only a subset of JPL works under Microsoft Windows. This subset includes | |
37 | the JNI extension and the JPL module. This is enough for you to embed | |
38 | Java in Perl, but not Perl in Java. | |
39 | ||
40 | This has only been tested with the Sun JDK 1.1.8. I haven't tested it | |
41 | with JDK 1.2 (aka Java 2) or any Microsoft implementation of Java. | |
42 | ||
43 | Kaffe | |
44 | ----- | |
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45 | You might notice some mention of Kaffe (www.kaffe.org) in the source files. |
46 | This is because support has been added for Kaffe for JNI:: and JPL::. In | |
47 | other words, you can now call to Java from Perl using Kaffe. | |
48 | ||
49 | You'll likely need the a checkout circa 2000-12-03 or later from Kaffe's | |
50 | CVS. It has been verified that Kaffe 1.0.5 definitely *will not work*. | |
51 | Kaffe 1.0.6 might work, but the CVS tree definitely works (as of | |
52 | 2000-12-06). | |
53 | ||
54 | You can get the CVS tree from: | |
55 | ||
56 | cvs -z3 -d ':pserver:readonly@cvs.kaffe.org:/cvs/kaffe' checkout kaffe | |
57 | ||
58 | (password is 'readonly') | |
b83c0eaa | 59 | |
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60 | What the heck is JPL? |
61 | --------------------- | |
62 | JPL is a hybrid (to use the polite term) language. It's basically Java | |
63 | in which the methods can optionally be implemented by Perl code. A | |
64 | preprocessor called "JPL::Compile" looks at your .jpl file and spits | |
65 | out the appropriate .java, .c, .h, .pl, and .so files to accomplish the | |
66 | desired task. Hopefully a lot of those files can go away in the future | |
67 | as jpl mutates into a Perl-to-Java compiler. The long-term goal is for | |
68 | jpl to be able to take a pure Perl file and spit out a java .class | |
69 | file. This initial version of JPL is an attempt to begin to mesh the | |
70 | semantics of Java and Perl. Some people may find it useful in its | |
71 | current form, but you should know right up front that we've still got a | |
72 | ways to go with it. A journey of a thousand miles continues with the | |
73 | second step... | |
74 | ||
75 | JPL Syntax | |
76 | ---------- | |
77 | JPL syntax is trivial, given that you know Java and Perl. Pretend like | |
78 | you're writing a native Java method, but say "perl" instead of | |
79 | "native", and then instead of omitting the body of the method, put your | |
80 | Perl code in double curlies. (See Sample.jpl for an example.) | |
81 | ||
82 | Calling back from Perl to Java is done through the JNI (Java Native | |
83 | Interface). No weird transmogrifications are done by the preprocessor | |
84 | to your Perl code--it's all normal Perl. The preprocessor just wraps | |
85 | it up into funny subroutines you don't see unless you peek at the .pl | |
86 | file it generates. | |
87 | ||
88 | Installation | |
89 | ------------ | |
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90 | There are two ways to install JPL. |
91 | ||
92 | The first way gives you the ability to embed Perl in Java programs. You | |
93 | can also call back into Java from your embedded Perl programs. This should | |
94 | work well with most JDKs, and is the only option for people using a JDK | |
95 | that uses green threads (see your JDK documentation). | |
96 | ||
97 | The second way lets you embed Java in Perl, but doesn't provide support | |
98 | for the other direction. This is good, in theory, if you need to work with | |
99 | a lot of Java classes from within Perl. I say "in theory," because this | |
100 | doesn't actually work a lot of the time. To use this second way, you | |
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101 | must be using a JDK with native threads. Please see README.JUST-JNI for |
102 | details. | |
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103 | |
104 | At this point, the second way is the only way to use JPL under Microsoft | |
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105 | Windows, and probably the only way to use JPL if you're using a version |
106 | of Perl compiled by someone else (such as the Perl that comes with RedHat). | |
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107 | |
108 | Installation the First Way (All of JPL) | |
109 | --------------------------------------- | |
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110 | Run "install-jpl". You have to tell it whether you want to use the |
111 | current directory for JPL_HOME or some other directory. Everything | |
112 | else should take care of itself, except that after install-jpl | |
113 | writes the setvars program, you are responsible to invoke it properly | |
114 | before any JPL applications can be compiled under the current shell. | |
115 | ||
116 | sh: eval `setvars -sh` | |
117 | csh: eval `setvars -csh` | |
118 | perl: eval `setvars -perl`; | |
119 | ||
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120 | install-jpl has been tested under: |
121 | ||
122 | Solaris 2.5.1 SPARC, GCC 2.8.0, Perl 5.005_03, JDK 1.1.7 | |
123 | Debian 2.1 x86, Perl 5.005_60, JDK 1.1.7v3 | |
124 | ||
125 | ******************** | |
126 | Solaris 2.5.1 Users: | |
127 | ******************** | |
128 | ||
129 | NOTE: Under Solaris 2.5.1, you may get an error message when install-jpl | |
130 | builds Sample.jpl: | |
131 | ||
132 | You must install a Solaris patch to run this version of the Java | |
133 | runtime. Please see the README and release notes for more | |
134 | information. | |
135 | Exiting. | |
136 | ||
137 | This is apparently a spurious message, and it has been reported to | |
138 | Sun. Although this message aborts the installation, all of JPL is | |
139 | installed by the time this message is reached. To recover and continue, | |
140 | run setvars as described above, cd to the Sample directory, and type | |
141 | 'make' to continue building. You can then run 'java Sample' to test the | |
142 | example. | |
143 | ||
144 | Unfortunately, each time you use 'make' to build a JPL application, | |
145 | it will abort when it tries to run 'perl -c' on the generated .pl | |
146 | file. However, you can continue building by typing 'make' again. | |
147 | ||
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148 | Mailing List |
149 | ------------ | |
150 | To subscribe to the jpl mailing list, send an email message to | |
151 | jpl-subscribe@perl.org. | |
152 | ||
153 | CVS Access | |
154 | ---------- | |
155 | Information on accessing the bleeding edge JPL via CVS can be found at: | |
156 | ||
157 | http://users.ids.net/~bjepson/jpl/cvs.html | |
158 | ||
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159 | More Info |
160 | --------- | |
161 | ||
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162 | You can look at the Sample and Test directories, as well as the ../eg |
163 | directory for examples. | |
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164 | |
165 | Perhaps the most important bit of advice we can give you is to watch | |
166 | ||
167 | http://perl.oreilly.com | |
168 | ||
169 | for further information on how to get further information. | |
170 | ||
171 | Have the appropriate amount of fun. |